Hydraulic Solenoid Valve for an Automatic Transmission of a Vehicle

Abstract

The present invention relates to a hydraulic solenoid valve for an automatic transmission of a vehicle, which moves an armature and a spool upward or downward by means of magnetic force so as to open/shut an inlet and an outlet, characterized in that an air gap is formed between a circumferential surface of the armature and a circumferential inner surface of the movable guide body, thereby reducing mechanical processing error or assembly error, and enhancing hydraulic performance and gear shifting performance.

1 . A hydraulic solenoid valve for an automatic transmission of a vehicle, comprising:
 a valve housing having an inlet, a control hole and an outlet in an upper portion thereof;   a spool disposed in the valve housing so as to be movable vertically so that the inlet and the outlet are opened or closed depending on upward or downward movement of the spool;   an armature disposed in the valve housing below the spool, the armature moving vertically using magnetic force and moving the spool vertically;   a movable guide body installed in the valve housing, the movable guide body having a hollow hole in which the armature is vertically disposed so that the movable guide body guides the vertical movement of the armature;   a magnetic force generation unit provided in the valve housing, the magnetic force generation unit generating magnetic force; and   a first bushing member and a second bushing member disposed in the hollow hole of the movable guide body at positions spaced apart from each other in the vertical direction by a predetermined distance, the first and second bushing members being provided around the armature,   wherein the movable guide body has a first bushing insert depression and a second bushing insert depression formed in a circumferential inner surface of the hollow hole at positions spaced apart from each other in the vertical direction by a predetermined distance, and the first bushing member and the second bushing member are respectively disposed in the first bushing insert depression and the second bushing insert depression, and   a circumferential inner surface of the first bushing member and a circumferential inner surface of the second bushing member protrude from the circumferential inner surface of the hollow hole so that an air gap is defined between a circumferential outer surface of the armature and the circumferential inner surface of the hollow hole.   
     
     
         2 . The hydraulic solenoid valve for the automatic transmission of the vehicle as set forth in  claim 1 , wherein the first bushing member and the second bushing member are coaxially disposed. 
     
     
         3 . The hydraulic solenoid valve for the automatic transmission of the vehicle as set forth in  claim 1 , wherein a drain hole is formed in a lower surface of the valve housing to drain air and residual oil out of the valve housing. 
     
     
         4 . The hydraulic solenoid valve as set forth in  claim 1 , further comprising
 a stopper provided in a lower surface of the armature, the stopper being made of non-magnetic material.   
     
     
         5 . The hydraulic solenoid valve for the automatic transmission of the vehicle as set forth in  claim 1 , wherein a hardening layer is formed on the surface of the armature to enhance a surface strength of the armature. 
     
     
         6 . The hydraulic solenoid valve for the automatic transmission of the vehicle as set forth in  claim 1 , wherein the spool is elastically supported by a spring disposed in an upper portion of the valve housing. 
     
     
         7 . The hydraulic solenoid valve for the automatic transmission of the vehicle as set forth in  claim 1 , wherein the magnetic force generation unit comprises:
 a coil assembly comprising a bobbin enclosing a circumferential outer surface of the movable guide body, and a coil wound around the bobbin; and   a core unit disposed above the armature at a position spaced apart therefrom, the core unit using magnetic force generated from the coil assembly to attract the armature.   
     
     
         8 . The hydraulic solenoid valve for the automatic transmission of the vehicle as set forth in  claim 7 , wherein
 a vertical moving shaft protrudes from a lower end of the spool, the vertical moving shaft coming into contact with an upper surface of the armature, and   the core unit has a shaft hole in which the vertical moving shaft is disposed, and an insert depression formed in a lower surface of the core unit so that a portion of an upper end of the armature is inserted into the insert depression, and   the vertical moving shaft protrudes into the insert depression through the shaft hole.